A truss is a structure consisting of members / elements that takes only tension or compression and no bending is induced what so ever.
The members are connected with a guzzet joint that is either riveted, bolted or welded in such a way that has only axial forces are induced in the structure.
The reason behind axial forces is the reason that the external loads are applied in such a way that their effects are in the form of forces applying only on joints.
Definition of Truss
A truss is a very Useful structures as far as weight of building is considered.
One more definition is that truss is a structural member that is assembled in such a way that forces are applied only on the ends.
Types of Trusses
A truss can be of two types as far as workspace is considered;-
- Planar truss
- Space truss
Planar truss is that in which members lie in a two dimensional plane while space truss lies in three dimension.
A truss is composed of three basic parts, one is top chord, the beam at the top which is usually in compression, bottom chord, beam at the bottom which is usually in tension, webs are interior beams.
There are variety of trusses available depending on the requirement including span length and loading condition.
Basically two types of trusses exists :-
- Bridge Trusses
- Roof Trusses
1. Pratt Bridge Truss
It includes vertical members and diagonals that slope down towards the center. The diagonal members are subjected to tension while vertical members are subjected to compression.
2. Howe bridge Truss
It includes vertical members and diagonals that slope up towards the center.
3. Baltimore Bridge Truss
A Baltimore truss has additional bracing in the lower section of the truss to prevent buckling in the compression members and to control deflection.
4. K Bridge Truss
A truss in the form of a K due to the orientation of the vertical member and two oblique members in each panel is known as a K bridge Truss
5. Warren Bridge Truss
It consists of longitudinal members joined only by angled cross-members, forming alternately inverted equilateral triangle-shaped spaces along its length.
6. Bailey Bridge Truss
It is designed for military use, the prefabricated and standardized truss elements may be easily combined in various configurations to adapt to the needs.
1. Pratt Roof Truss
It uses vertical member for compression and horizontal members to respond to tension and is most efficient under static and vertical loading.
2. Fink Roof Truss
They are used for longer spans having high pitch roof, since the web members in such truss are sub-divided to obtain shorter members.
3. Howe Roof Truss
It is a roof truss with vertical web members to take tension forces and with angled braces to take compression.
4. Warren Roof Truss
In warren roof truss diagonal members are alternatively in tension and compression are used in a building ranging from 20-100 m in length.
5. King Post Roof Truss
A king post extends vertically from a crossbeam to the apex of a triangular truss. It connects the apex of the truss with its base, holding up the beam (in tension) at the base of the truss.